The present invention relates to separator spacers for hermetically sealed double glazed window units, and particularly provides an improved corner piece for connecting the ends of adjacent spacers.
Spacers for separating the glass panels of a hermetically sealed doubled glazed unit are generally formed from a strip of metal which is roll formed into a tube. The tubular spacer extends around the glazing unit between the outer margins of the glass panels, sealant material being used between the glass and the sides of the spacer. In order to prevent any condensation of moisture between the glass panels which would interfere with visibility, the spacer tube contains a desiccant which absorbs any such moisture. In order for the desiccant to be effective, air passages must be provided between the inside of the spacer and the space between the glass panels, however any such air passages must be small enough to prevent the desiccant from falling from the inside of the spacer into the space between the glass panels.
In some previously known spacers, the edges of the strip of metal have been formed with inturned flanges merely butted together. With such constructions, however, the spacer tends to deform and spread at the junction between the flanges when the spacer is cut, leading to poor sealing between the glass panels and also opening up of the joint between the edges of the strip so that desiccant can fall from the spacer. In other known spacers, the edges of the strip have been locked together by means of a roll formed seal. Such seals, as now known, prevent distortion of the spacer when cut, but have two draw-backs, namely that it is necessary to form some kind of air passages between the inside and the outside of the spacer (requiring a separate operation), so that the desicant can be effective as described, and furthermore the joints as produced have been on the outside of the spacer and present a somewhat unattractive appearance since they are visible when looking through the glass panels of the unit.
My Canadian Pat. No. 1,008,307 issued Apr. 12, 1977 provides a method whereby a metal strip can be formed economically into a spacer for double glazed window units, the spacer being formed with a joint which prevents distortion during cutting, which does not detract from the appearance of the spacer, and in which air passages are provided without any separate forming operations.
The aforesaid patent also describes a spacer for hermetically sealed double glazed window units formed from a metal strip and having a joint between the edges of the strip, in which the joint includes one edge portion of the strip bent to form an outwardly facing groove and another edge portion of the strip bent to form an inwardly extending lip, which lip is of lesser width than the depth of the groove.